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damg writes "Anybots, which is three guys led by Trevor Blackwell, has developed the first robot that walks like we do, by dynamically balancing itself rather than being pre-programmed for walking like Asimo. The video shows the robot walking and being pushed by another 'bully' robot to demonstrate that it can't easily be pushed over."

You are correct from a technical standpoint, but the notion that a robot (which I believe Segway is) autonomously balancing itself is a breakthrough of some sort pales because Segway did it first, albeit in one dimension.

Even the title specifically mentions bipeds.
And the Segway was certainly not the first inverted pendulum to be controlled. It was just the first to make it into a stupid roll along machine to ride on.

Gets out of bed, goes to the fridge, pulls out a soda and pours a coffee, then sits at the computer for 12-20 hours stopping only to walk to the door to receive food deliveries, go to the fridge to get another soda, and to the bathroom to remedy the situation that the previous two types of activities has caused?

This is ways more impressive than you'd guess from the video, which doesn't look much different from all the other walking biped robot video (it's less shiny than most). Since this always pops up [slashdot.org] and always has to be explained [slashdot.org]:

not dynamically balanced:

When the robot (e.g Asimo) moves, it's center of gravity is ALWAYS above the foot it is standing on. As a consequence, the robot could freeze at any moment without falling. Humans can walk that way, but it's slow.

dynamically balanced:

The center of gravity is not above the foot, basically it's falling forward, the motion cannot be stopped without falling. Much faster to move, much harder to calculate. Anybots managed this, which makes their bots a great achievement. We move this way.

ASIMO _absolutely_ dynamically balances. I have one in my lab at CMU and have worked with walking humanoids [kuffner.org] for years.

First of all, static stability means the center of gravity (CoG) is inside the base of support (the convex hull of the ground contact points).

Dynamic stability is much more difficult to analyze because it involves stability over time. The velocities of any moving parts of an articulated body induce linear and angular momentum that can result in a dynamic stability over time _without_ having any of the intermediate poses being statically stable.

The center of gravity absolutely _does not_ always stay above the support leg for ASIMO. If you try to freeze his pose during the middle of a step it will fall over.

Instead, ASIMO is controlled to keep the Zero Moment Point (ZMP) always inside the convex hull of the contact points. The ZMP (related to the Center of Pressure) is the point on the contact surface where the sum of all torques (moments) is zero. For a given walking trajectory, if the ZMP always stays inside the base if support, then the walk is dynamically stable.

There have been numerous humanoids that use the ZMP formulation to control and maintain dynamic balance while walking (e.g. Honda P2, P3, ASIMO, U. Tokyo H6, H7, AIST HRP2, Waseda Wabian 1, 2, KAIST Hubo, Toyota Partner Robots, Sony QRIO and many more). ALL of these robots are dynamically balancing and are definitely NOT statically stable.

Kuffner (above) is right, of course. Dynamically stabilized walking has been around for years. It's not easy to do, but it's been done. Raibert first did it in the 1980s. See
his book, "Legged Robots that Balance".

Most of the self-balancing walkers, as Kuffner points out, use a ZMP-based approach. This works for walking, although it's not quite enough for effective running.

Many of the dynamically balanced robots can rebalance after a shove. BDI's Big Dog can. [bdi.com] So can some Japanese hobbyist robots.

If you're not up to date on how far along Japanese hobbyist robotics has progressed, see these videos of this month's humanoid robot soccer match [robots-dreams.com]. These robots are mostly manually controlled, but have computers managing some functions. Many have rate gyros to assist with balance. Gradually, the computers and sensors are taking over more of the control. The hobby robotics manufacturers in Japan now have about 70% of the functionality of Asimo at 2% of the price. There are hobbyist robots with WiFi links and cameras on board. A few more improvements and you'll be able to do all the
Asimo stuff with a $1500 robot. But it will only be about 60cm high.

Yes. He founded the Leg Lab at Carnegie Mellon, and later took it to MIT where it got even more famous. Then he left for Boston Dynamics, which created the "big-dog" robot that has been on slashdot. Gill Pratt continued the MIT Leg Lab work on force-based actuation and dynamic walking for some time after that.

I'm glad to hear that someone has said it. Yes, this is by far not the first dynamically balancing robot; and in this case, to be honest, i'd probably wait a bit and improve the bot's look/performance before announcing anything.

The Sony SDR 4X/QRIO has one of the more impressive ZMP implementations that i've seen in a while. Too bad that the project got killed.

Watch the video again. The cords are hanging loosely and jiggle when it moves. If they were supporting him, they would obviously be taut, like an actor hanging from a wire or a kid on a swing. It makes plenty of sense for the cords to be there to provide power and transmit/receive data. Without the added weight of a battery and computer, they can work on getting the mechanism to work first, then work on getting it to work untethered under heavier weight loads later.

You also may have noticed a mobile frame on casters that surround the robot. Most of the time, I'm sure they connect this robot to a harness so it doesn't fall down. We're not talking about pride here. When your robot falls and breaks something, that shit gets expensive!

Basically, this is like a child riding a bike with training wheels. Just because they are there doesn't mean they're being used all the time at that given moment.

This robot is cheating by starting out at a standing position. Figuring out how to get from crawling or lying down to a standing position is probably the hardest part of walking, as any baby can tell you, Including my 9 month old girl.

This robot is cheating by starting out at a standing position. Figuring out how to get from crawling or lying down to a standing position is probably the hardest part of walking, as any baby can tell you, Including my 9 month old girl.

I'm not sure I agree with this. I guess it depends on what you mean by "hard".

Babies first learn to "stand" with assistance, and they do this for several months. At first the assistance is from an adult who holds them up so that all the baby is really doing is supporting his weight, but not balancing. Then the adult switches to just holding the baby's hands, so that the baby has to do much of the job of balancing, but the adult handles the rest and provides a safety net. Then the baby learns how to

What I thought was fascinating is that the strides it took looked so much like an infant that is learning how to walk.... slowly, one foot at a time, adjusting balance with every step using hips almost exactly the way an infant does, in a gradual endeavor to develop a rhythm.

Back in the day, I worked as a sysadmin in a NASA AI/Robotics Lab. Your comment reminds me of what one of the researchers said to one of the other researchers who had a child: How's your natural intelligence project coming?

Yes, it's geeky. But it was pretty funny for a group of AI researchers.

This is a cool robot, but the claim of being the first "dynamically balancing robot" is an overstatement. There have been many dynamically balancing robots before, the most famous being Honda's P2 unveiled in 1997. After that, there have been dozens of walking and dynamically balancing humanoids.

What I think the story _should_ point out that is very impressive is:

1) The robot uses pneumatic actuators, which are notoriously difficult to model and control. Almost all of the current dynamically balancing and walking humanoids use electric motors (e.g. ASIMO).

2) Anybots claims to have some "learning" in their controller. Although they don't have any papers about what they are doing, perhaps they are using some clever statistical modeling and feedback to adaptively control and regulate the robot's stability.

BTW, I had a chance to meet Trevor Blackwell a few years ago when he visited my lab. He is definitely a talented engineer with a vision for the future. Several years ago he made Slashdot when he announced his homemade Segway:

The article claims that this is different from ASIMO in that it is unprogrammed. Perhaps this means that the feedback from the gyro
is used more directly?

In any case, this certainly looks like my friend getting over hip replacement surgery. I wonder if one application would be in
working out better models of physical therepy. Give the robot the same change in leg length and muscle weakness, see how it
compensates, then have the patient imitate. The recovery buddy?

This is obviously a great advancement with enormous potential. But apart from aesthetics I would have thought four legs more practical than two in many circumstances.

DARPA (the US military research folks who helped bring us the Internet) is currently funding
Big Dog [wikipedia.org] which I think is has far more potential, because however you calculate it, a quadruped has to have more stability than a biped. Though, in no way do I wish to detract from the achievements of Dexter.

Folks, if you want to see cool robotics, check out that video. Nearly every robotics achievement always seems to blah when you finally see what these robots can do. Yes, on a technical level, we've made a hell of a lot of progress (I've never managed to make a robot dynamically walk more than 2 or 3 slow steps myself, so I can appreciate just how hard this is), but on an asthetic level, they look so.. robotic. Even Asimo leaves something to be desired.Check this BigDog video out, it's quite amazing. It look

Ah! That robot is scary! Why does it have to look like two skinny guys in skintight pants have their torsos stuck in the chassis? If there are two guys in there, why are they making that awful two-stroke engine sound?

Watching the video, I couldn't help but notice that this lacked arms. It strikes me as rather odd to see this, because arms are one of the key features of human balance, but then again they do make for more variables.

This self-balancing robot resembles the Terminator in many ways, except or course, that it can't chase me, and it doesn't have any arms. I suppose that swaying arms might actually improve balancing once it can walk faster with longer steps. Interesting work...

Not sure why I thought of this and I have no experience with dynamically balanced robots...but...

If the gyroscope and such balancing mechanisms are so incredibly sensitive, perhaps it's possible for the sensors to get overloaded from very fast movement and the robot would lose his balance. In essence, he would get dizzy.

At this stage, I doubt you could call the robot falling in the video getting dizzy...but still, it's food for thought.

Initially, they just used a lab intern to push/bully the robot.After dozens of "tests", the first robot declared war on the human race, and had to be burned!It was determined that building a Pusher Robot, would save lives and money, and therefore built.

There's been several comments related to pusher/shover robots, the terrible secret of space, and "pak chooie unf". For those who don't know what these refer to, see the ICQ prank that started it [somethingawful.com] and the flash animation/song [devilducky.com] inspired by it.

Isn't dynamically balancing easier to do with arms? Not to mention, they allow you to move faster and they can catch you if you fall.

I'd bet it would not be too difficult, certainly not easy but compared to their work to this point it'd be trivial, to add some arms and significantly improve the robot's ability to walk... perhaps even jump and/or run... they could even have it catch itself if it falls.

I think running and jumping robots are quite far away. The problem is that modern mechanical actuators can't efficiently generate the kind of power (force times speed, equivalent to energy per unit time) needed for a jump or a sprint. You could get a jump with springs coiled by a slower drive-train, but that kind of explosive, uncontrolled release would not be coordinated.

At this point a shuffling jog is a (serious) programming challenge, but for a running or jumping robot you would need physical techn

From all appearances, the actuators used on the robot on the are plenty powerful and fast to make a small jump... I'm not thinking of replacing Michael Jordan with a bot or anything.Jumping takes great strength in the legs, but equally important is a good arm swing action... the arms play a tremendous roll in making a jump, as they direct a large portion of your weight in the vertical direction and they act as stabilizers in flight.

I honestly belive that a jumping robot will come well before a jogging or ru

I don't see running as a problem. It's not a power problem, it's a reflex problem and this can be solved by using a spring system (two semi-curves held in opposition to each other) in addition to the servos to get them started/stopped. Basically the robot just needs to start slow and build up potential energy in the springs each time it performs a longer controlled fall, that flexes the springs and is redirected forward by the foot/ankle. At least that's how a good long distance runner does it... as little

Despite my best efforts, I cant help but apply human characteristics to Dexter the robot. I notice he (dammit! it..) has a rather ugly face, thus i'm naturally repelled by it. Stupid human brain, this is a wonderful demonstration of advanced robotics! Appreciate it! Its interesting though, logic telling me this is quite interesting, unconscious judgment saying ewww. Anyone else think along the same lines?

after reading the summary, I was expecting it to be pushed while it was walking. Instead it was standing around like a little punk while the other robot was trying to pick a fight or something.. "Yeah, biatch. What you gonna do about it, huh? Huh?"
Pretty cool video, though.

Mr. Blackwell couldn't be reached for comment. A source close to him mentioned he was meeting with KITECH's creator of EveR-1, Baeg Moon-hong in San Marcos, CA with Abyss Creations, manufacturers of the Real Doll. While dumpster diving in Mr. Blackwell's refuse, multiple pages were found about a secret project code-named: C.H.E.R.R.Y.2000.

Asimo doesn't walk like we do. Dexter (this new one) looks like a 10-month-old trying to learn to walk. A robot built to walk in the same vein as Asimo will never be able to walk as easily as a human does. There's way too many variables that would have to be hard coded in (as Asimo's programming is).

True. I think the goal is to be able to make it over rough terrain and step over rocks rather than having to crush them under the weight of the robot. Then you can start attaching weapons and send them in. Dexter, keep your head low.